At present the geothermal deposits exploitation is based on the utilisation of hot fluids, steam or water coming from the same deposit, conveyed to the surface by drilled wells.
In the case of hot rock deposits, without natural water or steam, the usual procedure consists of drilling and fracturing rock by blasting or with hydraulic methods, then water is circulated towards a second well used as extractor of the hot steam produced.
Normally, very important quantities of external water are required by this system.